3534 x 5315 px | 29,9 x 45 cm | 11,8 x 17,7 inches | 300dpi
Date de la prise de vue:
25 mai 2005
Lieu:
Ol Doinyo Lengai, aerial view towards the east from 10000 feet, cone on the crater floor, Tanzania
Informations supplémentaires:
Ol Donyo Lengai (2.960 m, 9.711 ft) is a volcano located in Tanzania and is part of the volcanic system of the Great Rift Valley in eastern Africa. The volcano Empakai in the background. Ol Donyo Lengai is active and the crater has slowly filled with lave pouring over its edge since 1998. The resulting volcanic landscape is different from any other in the world. Ol Donyo Lengai is unique among volcanoes in that it produces natrocarbonatite lava, an unusual type of carbonatite, whereas most lavas are rich in silicate minerals, the lava of Ol Donyo Lengai is rich in the rare sodium and potassium carbonates, nyerereite and gregoryite. Due to this unusual composition, the lava is erupted at relatively low temperatures (approximately 500-600 degrees Celsius). This temperature is so low that the molten lava appears black in sunlight, rather than having the red glow common to most lava. The sodium and potassium carbonate minerals of the lava formed by Ol Donyo Lengai are unstable at the Earth's surface and susceptible to rapid weathering, quickly turning from black to grey in color. The cone-building stage of the volcano ended about 15, 000 years ago. Ol Donyo Lengai means “Mountain of God" in the language of the native Maasai people.The volcano Empakai in the background.
